Inductively coupled plasma mass spectrometry （ICP-MS） is the most commonly used technique to deter- mine the abundances of trace elements in a wide range of geological materials. However, incomplete sample digestion...Inductively coupled plasma mass spectrometry （ICP-MS） is the most commonly used technique to deter- mine the abundances of trace elements in a wide range of geological materials. However, incomplete sample digestion, isobaric interferences and instrumental drift remain obvious problems that must be overcome in order to obtain precise and accurate results, For this reason, we have done many experi- ments and developed a set of simple, cost-effective and practical methods widely applicable for precise and rapid determination of trace element abundances in geological materials using ICP-MS. Commonly used high-pressure digestion technique is indeed effective in decomposing refractory phases, but this inevitably produces fluoride complexes that create new problems. We demonstrate that the fluoride complexes formed during high-pressure digestion can be readily re-dissolved using high-pressure vessel at 190 ℃ for only 2 h for 50 mg sample. In the case of isobaric interferences, although oxide （e.g., MO^＋/M^＋） and hydroxide （e.g., MO^＋/M^＋） productivity is variable between runs, the （MO^＋/M^＋）/（CeO^＋/Ce^＋） and （MOH^＋/M^＋）/（CeO^＋/Ce^＋） ratios remain constant, making isobaric interference correction for all other elements of interest straightforward, for which we provide an easy-to-use off-line procedure. We also show that mass-time-intensity drift curve is smooth as recognized previously, for which the correction can be readily done by analyzing a quality-control （QC） solution and using off-line Excel VBA procedure without internal standards. With these methods, we can produce data in reasonable agreement with rec- ommended values of international rock reference standards with a relative error of 〈8% and precision generally better than 5%. Importantly, compared to the widely used analytical practice, we can effectively save 〉60% of time （e.g., 〈24 h vs. 〉60 h）.展开更多
This paper investigates the use of a combined hydrogen, heat, and power (CHHP) system for Omar Al-Mukhtar University campus using local resources. Based on previous local resource assessment studies, the hydrogen team...This paper investigates the use of a combined hydrogen, heat, and power (CHHP) system for Omar Al-Mukhtar University campus using local resources. Based on previous local resource assessment studies, the hydrogen team of Omar AL-Mukhtar University (OMU) selected the fuelcell energy DFC4000TM unit. This study shows that the CHHP system can provide electricity to power the university campus, thermal energy for heating the anaerobic digester, and hydrogen for transportation, back-up power and other needs. Consequently, using the alternative fuels and renewable energy resources for OMU campus can lower fossil fuel consumption and, therefore, greenhouse gas emissions (GHG).展开更多
With the increase in global life expectancy,the research on the specific digestive patterns of the elderly is becoming highly essential.We simulated the digestion process of older individuals in vitro and investigated...With the increase in global life expectancy,the research on the specific digestive patterns of the elderly is becoming highly essential.We simulated the digestion process of older individuals in vitro and investigated the effects of various high hydrostatic pressure(HHP)treatments on the protein structure,digestibility,and antioxidant activity of whey protein isolate(WPI),as well as the antioxidant peptides produced from its digest.The HHP treatment specifically affected on the secondary and tertiary protein structures along with the free sulfhydryl content of WPI.Protein microstructure revealed a significant increase in the number and depth of pores.Highest in vitro digestibility and cellular antioxidant activity was observed after HHP treatment at 600 MPa for 30 min.In the intestinal digest,15 antioxidant peptides were identified whose characteristics matched those of bioactive peptides.Of these,the LGSDMEDLR peptide sequence had the highest"-CDOCKER Energy"and formed the salt bridge,attractive charge,conventional hydrogen bond,carbon hydrogen bond,and van der Waals with Arg380,Arg415,Arg483,Tyr334 and Asn382,which all located in the binding site of the Keap1-Nrf2 interaction.Overall,HHP appeared to be a potential method for the application of dairy products among the elderly.展开更多
基金supported by National Natural Science Foundation of China(41130314 and 41630968)Chinese Academy of Sciences Innovation Grant(Y42217101L)+1 种基金Qingdao National Laboratory for Marine Science and Technology(2015ASKJ03)Marine Geological Process and Environment(U1606401)
文摘Inductively coupled plasma mass spectrometry （ICP-MS） is the most commonly used technique to deter- mine the abundances of trace elements in a wide range of geological materials. However, incomplete sample digestion, isobaric interferences and instrumental drift remain obvious problems that must be overcome in order to obtain precise and accurate results, For this reason, we have done many experi- ments and developed a set of simple, cost-effective and practical methods widely applicable for precise and rapid determination of trace element abundances in geological materials using ICP-MS. Commonly used high-pressure digestion technique is indeed effective in decomposing refractory phases, but this inevitably produces fluoride complexes that create new problems. We demonstrate that the fluoride complexes formed during high-pressure digestion can be readily re-dissolved using high-pressure vessel at 190 ℃ for only 2 h for 50 mg sample. In the case of isobaric interferences, although oxide （e.g., MO^＋/M^＋） and hydroxide （e.g., MO^＋/M^＋） productivity is variable between runs, the （MO^＋/M^＋）/（CeO^＋/Ce^＋） and （MOH^＋/M^＋）/（CeO^＋/Ce^＋） ratios remain constant, making isobaric interference correction for all other elements of interest straightforward, for which we provide an easy-to-use off-line procedure. We also show that mass-time-intensity drift curve is smooth as recognized previously, for which the correction can be readily done by analyzing a quality-control （QC） solution and using off-line Excel VBA procedure without internal standards. With these methods, we can produce data in reasonable agreement with rec- ommended values of international rock reference standards with a relative error of 〈8% and precision generally better than 5%. Importantly, compared to the widely used analytical practice, we can effectively save 〉60% of time （e.g., 〈24 h vs. 〉60 h）.
文摘This paper investigates the use of a combined hydrogen, heat, and power (CHHP) system for Omar Al-Mukhtar University campus using local resources. Based on previous local resource assessment studies, the hydrogen team of Omar AL-Mukhtar University (OMU) selected the fuelcell energy DFC4000TM unit. This study shows that the CHHP system can provide electricity to power the university campus, thermal energy for heating the anaerobic digester, and hydrogen for transportation, back-up power and other needs. Consequently, using the alternative fuels and renewable energy resources for OMU campus can lower fossil fuel consumption and, therefore, greenhouse gas emissions (GHG).
文摘With the increase in global life expectancy,the research on the specific digestive patterns of the elderly is becoming highly essential.We simulated the digestion process of older individuals in vitro and investigated the effects of various high hydrostatic pressure(HHP)treatments on the protein structure,digestibility,and antioxidant activity of whey protein isolate(WPI),as well as the antioxidant peptides produced from its digest.The HHP treatment specifically affected on the secondary and tertiary protein structures along with the free sulfhydryl content of WPI.Protein microstructure revealed a significant increase in the number and depth of pores.Highest in vitro digestibility and cellular antioxidant activity was observed after HHP treatment at 600 MPa for 30 min.In the intestinal digest,15 antioxidant peptides were identified whose characteristics matched those of bioactive peptides.Of these,the LGSDMEDLR peptide sequence had the highest"-CDOCKER Energy"and formed the salt bridge,attractive charge,conventional hydrogen bond,carbon hydrogen bond,and van der Waals with Arg380,Arg415,Arg483,Tyr334 and Asn382,which all located in the binding site of the Keap1-Nrf2 interaction.Overall,HHP appeared to be a potential method for the application of dairy products among the elderly.
